Glass bending mould



Sept. 12, 1961 R. E. RICHARDSON GLASS BENDING MOULD Sept. l2, 1961 R. E. RxcHARDsoN 2,999,338

GLASS BENDING MOULD Filed Jan. 29, 1957 9 Sheets-Sheet 2 y .MM,%/ Mm Sept. `l2, 1961 R. E. RICHARDSON 2,999,338

GLASS BENDING MOULD Filed Jan. 29, 1957 9 Sheets-Sheet I5 @y Mw Sept. 12, 1961 R. E. RICHARDSON 2,999,338

GLASS BENDING MOULD ,Filed Jan. 29, 1957 9 Sheets-Sheet 4 MMMVMM Sept. 12, 1961 R. E. RICHARDSON 2,999,338

GLASS BENDING MOULD Filed Jan. 29, 1957 9 sheets-sheet 5 FON/ILD FICH/919050# i N mmm @Y MM5 M f Mm Sept. 12, 1961 Filed Jan. 29. 1957 rlllllxrllla R. E. RICHARDSON GLASS BENDING MOULD 9 Sheets-Sheet 6 RONA/p i Raw/@Jan MVM Sept. 12, 1961 R. E. RICHARDSON GLASS BENDING MOULD 9 Sheets-Sheet '7 Filed Jan. 29, 1957 Sept. l2, 1961 R. E. RICHARDSON 2,999,338

GLASS BENDING MOULD Filed Jan. 29. 1957 9 Sheets-Sheet 8 L5) FON/n.0 f. Flew/masa# 5y MWEMVM sept 12, 1951 R. E. RICHARDSON 2,999,338

GLASS BENDING MOULD Mwmywm UnitedStates Patent O Filed Jan. 29, 1957, Ser. No. 636,965

. 2 Claims. (Cl. 49`-67) This yinvention relates to improvements in lglass bending moulds of the concave type, and is particularly d1- rected towards a construction of mould designed for manufacture of bent vglass for use in the manufacture of laminated windshields.

Inparticular, the mould of the present invention is directed towards the manufacture of windshields having compound curvature, that is to say curvature in the transverse directionas well as in the longitudinal direction.

Theinvention is illustrated by way of example in the accompanying drawings which show various views of a concave, skeleton type glass bending mould. y

FIGURE 1 shows afront perspective general vie-w of the whole mould in lits A'curved orientation.

FIGURE 2 is a plan view on an enlarged scale of the right-hand half ofthe mould seen in FIGURE 1 with the parts in the flat orientation.

FIGURE 3 is a side view of the main parts of the mould half of FIGURE 2, these parts being in the haty orientation and in the loading position for receiving a fresh unbent sheet of glass.

FIGURE 4 isa view of the same parts as those seen in FIGURE 3,- but showing them in the positions occuied after bending a sheet of glass.l

`FIGURE 5 is a partial section on the line V-V in FIGURE 2.

FIGURE 6 is a fragment of FIGURE 5 illustrating the position ofthe glass prior to bending.

FIGURE 7 is a view similar to FIGURE 6', showing the parts at an intermediate stage during the bending operation.

FIGURES is a further view similar to FIGURES 6 and 7 and showing the position of the parts at the conclusion of the bending operation.

FIGURE 9 is` a detailed enlarged View of the pointer mechanism seen in FIGURESjS to 8.

FIGURE 10 is a partial sectiontaken ou the line X-X in FIGURE 2.

FIGURE ll is' a partial section taken on the line XI- XI in yFIGURE 2.

FIGURE 12,lis a rear view of a fragment of the apparatus as seen fromk the line XII--XII in FIGURE 2.

FIGURE 13 is kan enlarged broken away plan view of the upper heater unit carried by the mould.

FIGURE 14 4is a schematic circuit diagram of the heater connections. i i

FIGURE 15 lis al plan view of a sheet of unbent glass prior to mounting on the mouldfor bending.

FIGURE 1 6 isfa typical bent sheet of glass for forming a windshield `and illustrates a product of the mould seen in the foregoing drawings.

FIGURE 17 is a, transverse ,section on the XVII in FIGUREIG.

FIGURE' 18 isa transverse section through a typical hea-ting lehr.

me xvii- The mould consistsof vertically disposed elongated side'bars. 1 and 1 defining the edges of the main, central, stationary portion ofV the, mould. At each end of this central portion there is a pivotally mounted end portionZ. For simplicity with the exception of FIGURE 1 which shows anoverall` view, many of the figures have been restricted to illustration of only the right-hand end of the mould with the right-hand end mould portion 2,.

ICC

in mirror image. n

Each end portion 2 consists principally of -a bent vertically disposed bar 3 each end of which forms, in the curved orientation of the mould, a contiguous continuation of one of the side bars 1, 1. Each end of the bar 3 is connected by means of struts 4 to a semi-circular plate 5, the plates 5 serving to mount the end mould portion 2 pivotally on a pair of vertically upstanding plates 7. At this point, attention is directed to FIGURES l and 1l which demonstrate the manner of bracing the plates 5y with small side plates 5' secured to each side thereof, and the upstanding ends 7 on the plates 7, which maintain the parts in the correct position transversely. A bar 82 extends across the mould to join the two plates 7 and the bars 82 are themselves joined by a longitudinal bar 64.y Stops 83 project upwardly from each end of side bar 1 to prevent forward movement of the glass when in position on the mould. f

The struts 4 and plate 5 on each side'of the mould also serve to connect arms 6 toi each end mould portion 2. These arms 6 each carry a series of weights 8. The weights 8 cause movement of the end mould'portions 2 between the flat orientation of FIGURES'Z and 3 in Iwhich they are initially held by the weight and rigidity of the glass (shown at 9 in broken lines in FIGURE 3), and the curved orientation of FIGURES 1 and 4 to which themould moves when the glass begins to soften under the application of heat, allowing the weights to take charge. The final limit of this movement is determined by adjustable stops 10 supported on shelves 11 secured by brackets `12 Vto the lower part of respective side membersv a supporting framework 14 which consists of a series of i longitudinal and transverse angle members which form f an extendedhorizontal base or platform cn which the mould rests and by which it is supported on rollers 75 when passed through a heating lehr 76 (see FIGURE 18).

Mounted near each end of the main portion ofthe mould is a teeter device 15` which is used to provide additional supports for the glass intermediate the end tips 16 of the end mould portions 2 prior to and during bending. This teeter device 15 (see FIGURES l, 2 and 10) consists of ak transversely extending rod 17 which is pivot.- ally mounted at each end by hook members 18 in recesses 19 formed in the respective side members 1 and 1',

and a longitudinally extending, ygently downwardly bowed bar 20 on the front side of the mould, which is secured to the rod 17 and held in place by bracing members 21. On each end ythe bar 20 carries an upstanding lug 22 which lies closely inwardly of the side bar 1. In the flat orientation of the mould these lugs '22 project well above the level of the mould surfaces, as seen from FIG- URE 3, and serve to support the glass 9 in this position. As the mould turns into the curved oiientation of FIG- URE 4, the lugs Z2 come to lie below the curved plane defined by the under'surface of the glass 9 and no longer have any supporting action on the glass.

Mounted on the framework 14 by means of upwardly extending supports 2,3, aty each end of the mould, is a heater 24 which lies, in the llat orientation of, the

mould, just below the surface of the glass (see FIG. 3)

Adjacent the tip 16 of each end mould portion 2 there is mountedathermal ballastdevice. This thermal ballastdevice has two parts, an internal plate 25 (within the perimeter of the bar 3) and an external plate 26 (outside the bar 3). Both of these plates are mounted on a support structure 27 extending upwardly from the framework 14. The function of these plates is to delay heating of the extreme tips of the. glass during the early stage of the bending operation.

An adjustable stop 28 is also mounted on the support structure 27, this stop 28 determining the limit of downward' movement of the end mould portion 2 in the flat orientation.

Y Centrally of and'above the main stationary portionf'of' the mould there is mounted an upper heater assembly designated generally by the reference numeral 30. This assembly consists of a ilat sheet of perforated or expanded metal 31 mounted in a peripheral frame 32 of mild steel bars (see especially the cut-away view of FIGURE 13). Arranged beneath the sheet 31 and supported on transverse bars 33 are a number of heater elements 34, 35, and 36 each consisting of coils extending parallel to one another and in the longitudinal direction of the mould. Centrally of the assembly formed by such elementsthere is arranged a heater element 37 supported on longitudinal bars Z9 connected to thetransverse bars 33, the coils of the central element 37 extending parallel to Y. one another and in the transverse direction of the mould. As best seen from FIGURE -14 which provides a schematicl circuit diagram showing the electrical connections, a first circuit extends from a rst contact 38 through one of the end heaters 24, through `the element' 35 of the heater assembly 3i) and back through the other end heater 24 to a second contact 39, while a second circuit extends frorn a contact 40 through the heating elements 34, 36 and 37, back to a further contact 41.

When the mould travels along a heating lehr, the contacts 38 and 41 press upwardly against bus-bars 80 and 81 extending along the central upper part of the lehr 76. Attention is directed to FIGURE 18 which also shows conventional wall heaters 77 and ceiling heaters 78 in the lehr 76. t

. The positions of the contacts 38, 39, 40 and 41 in relation to `the remainder of the mould parts is best ap- `preciated from FIGURES 1, 2 and 5. Each of such contacts is secured to a pan' of spaced bars 42 by means of a pin 43 `whereby the assembly formed by such bars and the contact is pivotally mounted on the end of a forwardly bent upper portion of a support member 44 which projects upwardly from an insulated mounting 45 secured to the framework 14. The other ends of the two bars 42 areconnected together by apin 46 which bears against the rear surface of the support member 44 to limit clockwise rotation of the assembly, each such contact assembly tendiug to rotate in the clockwise direction because the weight of the parts on the right-hand side ofV the pivot pin 43 as seenin FIGURE 5 is greater than on the left-hand side. In use these contacts will be rotated slightly anticlockwise bythe bus-bars when in the lehr, so that the weight biasing these assemblies for clockwise rotation will provide the required contact pressure between contacts and bus-bars. Electrically conducting straps 47 connect each of the contacts to ixed wiring which is not fully shown in the structural illustrations, but is represented in the wiring diagram of FIGURE 14.

Contacts 33 and 40 receive current from bus-bar. 80 and contacts 39 and 41 from bus-bar 81. Thus as the mould travels through the lehr with the side which has been considered as the rear of the mould leading, contacts 38 and 39 will be the the bus-bars 80 and 81. These bus-bars do not extend along the iirst portion (preheating section) of the mould, but commence at a convenient position in the second or .he'nding section of the mould, where, once the vglass has been raised to a comparativelyhigh temperature in the pre-heat section, just the correct degree of further heating is employed to produce the required bending. Similarly, of course, the bus-bars do not extend into the ,rst to engage the ends of [s: annealing or cooling sections which follow the bending section.

Close control over the intense but short duration local heating provided by the end heaters 24 and heater 30 is important if accurate inish products are to be obtained. As previously mentioned, contacts 38 and 39 are rst to make contact with the bus-bars 80 and 81 and these energize both heaters 24 at the end elbows and heater element 35 which is comparatively centrally situated over the glass-perhaps somewhat on the side of the bar 1. Then, a few seconds later, the contacts 40 and 41 engage the bus-bars and elements 34, 36 and 37 are energized to provide intense local heating along the area above and slightly inwardly of the side bar 1 in the longitudinally central area of the mould. The division of the energy between two approximately equal. circuits and two pairs of contacts is found desirable in view of the heavy total load.

It will be noted that the bus-bars 80 and 81 extend along the lehr near the centre thereof, the contacts 38, 39, 40 and 41 being correspondingly positioned near the longitudinal centre of the mould.V This is in contradistinction to prior systems in which the bus-bars have been mounted to extend along the lehr near the side walls thereof. The present arrangement in which the bus-bars are centrally located has advantages in operation. Any slight twisting of the mould from its true orientation will be less likely to cause misalignment of contacts located centrally. Consequently the chance of the electrodes binding against ixed parts and arresting passage of the mould is much reduced. If one contact should become welded toa bus-bar as a result of excessive sparking, there would be less turning moment acting on the mould, and the elects of thermal expansion of the mould parts in producing misalignment will be minimised.. Finally contacts mounted as in the present mould will tend to interfere little with. the heat transfer conditions in the lehr, especially in respect of the end regions of the mould, which tend to be sensitive to shadow effects.

As best seen in FIGURES l, 2 and 5, the heater assembly 30 is secured to a base bar 48 extending along the rear edge of such assembly. Arms 49 projecting rearwardly from such bar 48 serve to mount the assembly pivotally [about pins 51 each carried by an insulated mounting 52 secured to the framework 14. Struts 50 increase the rigidity of the assembly. Further arms 53 project rearwardly `from the base bar 48 and converge to a lug 54 from which there depends a bar 55 which carries Iat its lower end a recess 55 which may be engaged over a projection 56 formed at the foot of `an upstanding framework 57, the head of which carries an adjustable stop 84 which determines the limit of downward movement of the heater assembly 30. The heater assembly 30 is thus pivotally movable between the full line position shown in vFIGURE 5, and the broken line position shown in the same figure (also illustrated in FIGURE 3 in full lines), the heater being moved to this position when it is desired to load or unload glass onto or from the mould.

As evident from FIGURES 1 and 2, the side bar 1' at the rear yof the mould, unlike the front side bar 1, is angled at each end so that the central portion of this bar s displaced towards the rear of the mould while being inclined inwardly (see also FIGURE 10). This part of the bar 1 is that on which the apron of the glass nally rests. Reference may be made at this point to FIGURE l5 which shows the shape of a sheetI of glass prior to bend- Y ing. This glass 9 Iis formed with the usual pointed ends Rearwardly of this central portion of the side bar 1 there is positioned a supporting shelf 63 which extends along behind such side bar 1 and is slightly curved downwardly at its ends, as best seen in FIGURE 12. When the glass 9 in the flat condition is placed on the mould, the apron 62 of the glass rests on the shelf 63. This is shown in FIGURE 6. The other points of support of the glass are the tips 16 of the end mould portions 2 and the lugs Z2 of the teeter devices 15.

IFIGURES 7 and 8 show two subsequent stages in the bending of the glass as the lmould is passed through the lehr. Both longitudinal and transverse bending takes place simultaneously. The forward edge of the glass tends to sink down into contact with the side bar 1. Due to the additional heat supplied by the heater 30, the transverse bending is greatest towards the rear of the mould and the glass bends down until it has iinally been bent to the required shape when it is supported wholly by the side members 1 and 1 and no longer rests on the shelf 63. This condition is shown in FIGURE 8.

The central transverse member 64 seen in these gures plays no part. in the glass bending operation but is merely a strengthening ymember extending between the two bars 82.

The degree of bending of the glass is detected by a pointer mechanism 65 seen in FIGURES 6, 7 and 8, and, on an enlarged scale, in FIGURE 9. This mechanism lconsists of a feeler 66 arranged to come into contact with a central portion (in the longitudinal direction) of the undersurface of the glass. The feeler 66 is pivotally mounted about a pin 69 supported by upstanding projections 70 on a base 71 which is secured to the framework 14. The remote end of 4the Ifceler constitutes a pointer 67 movable over a scale 68. The manner of operation of this device will be apparent from FIGURES 6, 7 and 8. The markings on thc scale 68 are formed 'by holes in the metal of which such scale is constituted, the desired ultimate position being indicated by the maximum number of holes, such as the four holes shown at 72. The scale 68 is formed as an upwardly extending end portion of an arm 73 which is also pivotally mounted about the pin 69, the position of such arm being adjustable by means of a screw 74. The feeler 66, 67 will be balanced so as to be slightly biassed towards the glass, ie. into the full line position as shown in FIGURE 9. On the other hand only a small force will be necessary to displacey it from this position. As best yappreciated from FIGURE 5, the pointer 67 and scale 68 yarereadil'y visible from the end of the mould for inspection through the conventional Viewing ports in the wall of the lehr.

I claim:

1. Apparatus for bending an elongated glass sheet into a compound curvature including a central region having a transverse curvature, comprising a skeleton type bending mould having a central mould portion provided with bars having shaped upper surfaces for supporting the lateral edges of the central portion of the bent sheet, a lehr comprising a bending zone provided with overhead heaters maintained at a temperature sufficient to cause bending of said glass sheet, ancillary heating means disposed closely above the central of the glass sheet and supported on said mould, said ancillary heating means serving to supplement the heating to which said central portion of the glass sheet is subjected by said overhead `heaters, and apertured reliector means having a heat reilective surface disposed closely above said ancillary heating means, said apertured reilector means serving to permit heat radi-ated from said overhead heaters to impinge on the glass sheet while increasing the proportion of radiant heat emitted by said ancillary heating means which impinges upon the centr-al portion of the glass sheet to cause said central portion of the glass sheet to assume said transverse curvature about 4an axis extending longitudinally of the glass sheet in alignment with said ancillary heating means.

2. Apparatus for bending an elongated glass sheet into a compound curvature including a central region having a transverse curvature, comprising a skeleton type bending mould having a central mould portion provided with a pair of spaced-apart, generally parallel bars having shaped upper sunaces for supporting the lateral edges of the central portion of the bent sheet, a lehr comprising a bending zone provided with overhead heaters maintained at a temperature suicient to cause bending of said glass sheet, ancillary heating means supported on said mould Iand comprising a plurality of horizontally spacedapart heating elements disposed to closely overl-ie said central portion of the glass sheet, said ancillary heating means serving to supplement the heating to which said central portion of the glass sheet is subjected by said overhead heaters, and a at sheet of perforated metal disposed closely above said ancillary heating means to overlie the entire extent of said heating elements, said at sheet of perforated metal serving to permit heat radiated from said overhead heaters to impinge on the glass sheet while increasing the proportion of radiant heat emitted by said ancillary heating means which impinges upon said central portion of the glass sheet to canse said central portion of the glass sheet to lassume said transverse curvature about an axis extending longitudinally of the glass sheet in alignment with said ancillary heating means.

References Cited in the tile of this patent UNITED STATES PATENTS 648,746 Houser May 1, 1900 833,436 lBorland etal Oct. 16, 1906 1,787,460 Wilcox n Jan. 6, 1931 2,111,392 Galey Mar. 15, 1938 2,176,999 Miller Oct. 24, 1939 2,348,279 Boyles et al. ..-4---- May 9, 1944 2,442,242 Lewis May 25, 1948 2,500,278 Dunipace Mar. 14, 1950 2,646,647 Bamford etal. July 28, 1953 2,663,974 Thomson Dec. 29, 1953 2,702,445 Iendrisak Feb. 22, 1955 FOREIGN PATENTSV 1,089,973 France Oct. 13, 1954 660,824 Great Britain Nov. 14, 1951 UNITED STATES PATENT oEElCE CERTIFICATE OF CORRECTION Patent No 2,999,338 September l2, 1961 Ronald Ef, Richardson hat error appears in the above numbered pat- I s hereby certified t hat the `said Letters Patent should read as ent requiring correction and t corrected below.

Column 3, line 35'i for 38 and 41" read 38 to 4l Signed and sealed this 2nd day of October 1962.

(SEAL) Attest:

ERNEST w. swTDEE DAVID L LADD Commissioner of Patents Attesting Officer UNETED STATESPATENT. oFFICE CERTFCATE F CURRECTION Patent No 999,338 September 12 1961 Ronald En Richardson It is hereby certified that error appears in the abo-ve numbered patrequring correction and that the -sad Letters Patent should read as ent corrected below.

Signed and sealed this, 2nd day of October 1962e (SEAL) Attest:

ERNEST w. SWIDER DAVID L- LADD Commissioner of Patents Attesting Officer 

